4020 transmission pump

[SVcummins]

My hydraulics have been taking longer and longer to start working after the tractor has set a couple days anc yesterday the hydraulics never did pick up oil and work like they should I’m thinking it’s time for a new transmission pump is there anything other than the screen and hydraulic filter that could be plugged

 

[MSM]

You might have a bunch of small internal leaks bleeding off charge pressure, not supplying adequate oil to the front pump. Remotes, loader valve, steering motor, three point cylinder. If you do find the charge pump bad, it can be replaced with a higher volume version to supply extra oil to the front pump

 

[Tx Jim]

Sounds typical for hyd check valve failure allowing oil to drain out of oil charge system back to sump when engine isn't running. JD did offer a check valve kit to help solve that problem.

 

[SVcummins]

Jim do you have a number for this check valve where does it
go ?
Thanks

 

[SVcummins]

I would like the bigger pump that would be nice

 

[Tx Jim]

(quoted from post at 15:30:41 07/06/20) Jim do you have a number for this check valve where does it
go ?
Thanks

No I don't & couldn't locate the part # by utilizing this forums search. That check valve has been discussed several times on this forum. IIRC there was an old YT member that discussed the installation but I can't remember his handle. Maybe Tim or some other member has the check valve part #.

 

[Hay maker2]

(quoted from post at 22:29:10 07/06/20)

(quoted from post at 15:30:41 07/06/20) Jim do you have a number for this check valve where does it
go ?
Thanks

No I don't & couldn't locate the part # by utilizing this forums search. That check valve has been discussed several times on this forum. IIRC there was an old YT member that discussed the installation but I can't remember his handle. Maybe Tim or some other member has the check valve part #.

 

[tomstractorsandtoys]

Don't be real quick to assume the trans pump is bad. The Deere service manual tells how to check for flow and Cliff Nelson had me make a gauge setup to check trans pump pressure. It is just a gauge put in the banjo fitting on top the hyd. pump. I thought I had a bad trans pump but I just needed to set the front pump pressure up a little higher. The check valve is the same as the valves in a hyd pump on a utility tractor. Deere has a bulletin that says what size to drill and tap the hyd line elbow to install it. Tom

 

[SVcummins]

So if I let it idle for about ten minutes I can cycle the loader clear up and down once before it’s starts getting jumpy and quits going up

 

[matthies]

The tap is a 3/4 16 UNF and thinking a 11/16 drill bit. The check valve goes in the elbow by the trans filter that connects to the line that goes to the front pump. Oring end of elbow. This is for a syncrorange transmission tractor.

 

[SVcummins]

I hope it isn’t but I’m afraid it might be . Better pull the screen again

 

[tomstractorsandtoys]

Mine would steer fine but did not want to raise the discbine completly and would not begin to run a hyd motor. I destroked the pump and readjusted the pressure to 2300 pounds. I first checked the hyd screen and changed filter. Then removed line down beside hyd filter to check how fast it would fill a 5 gal bucket. That was in specs so next we added a 300# pressure guage to the fitting on top the hyd pump and came up with a little less than 50# of pressure. I was told any pressure is ok and 50 was very good. Tom

 

[wore out]

Gerald J was the man!

Looks like his site is no more, but here's some info that the Wayback Machine grabbed:

https://web.archive.org/web/20150517050834/www.geraldj.networkiowa.com/4020si.htm

https://web.archive.org/web/20041018233454/www.geraldj.networkiowa.com/4020si.htm

Note reference to a Service Bulletin number.

 

[Tx Jim]

I thought YT old member was Gerald J but my Google & YT search came up with ZERO info.

 

[matthies]

Funny, last month I purchased the check valves from Deere and A&I and DEERE was cheaper.

 

[SVcummins]

Do you happen to know what size plug I need to plug the
supply Line to the main pump so I can run the test ?
Thanks

 

[SVcummins]

Ok. I wonder if I have some cylinder packing from a blown cylinder plugging something but the screen should ketch it ? Trying to figure out the size of the pipe so I can get a gauge and do the 5 gallon bucket test

 

[tomstractorsandtoys]

You do not plug the pump. Just drill and tap the banjo fitting on top the pump. Start tractor and do not work any hyd. functions. Will give trans pump pressure but not flow as that is a different test. Tom

 

[SVcummins]

Plug the line to the main pump to do the test according to the manual

 

[SVcummins]

Yt search hates me

 

[SVcummins]

Thanks

 

[mrslesq]

I was standing next to my running 4020 with a loader on it talking to a neighbor when it got very quiet. Turns out the pipe coming out of the transmission pump broke off. I am not saying that is your problem, but a good thing to check pipe when putting back together.

 

[SVcummins]

Anyone ever run the test as shown in the I&t manual just pull the filter and roll the engine over and see how much oil you get

 

[Tx Jim]

Yes I've utilized that test when performing hyd diagnostics but the results isn't as accurate as when utilizing a flow-rater when the oil GPM is measured under some pressure.

 

[SVcummins]

Thanks I need to get raking hay but I don’t want to fry the
transmission

 

[SVcummins]

Pulled the screen clean as a whistle pulled the filter clean as a whistle . I can cycle the bucket cylinders 9 times then I run out of oil tractor about 1200 rpm clutch engaged . Steering works fine and 3 point is fine . How much and what do I gain buy plumbing the loader into the rockshaft line will that help at all with this deal

 

[SVcummins]

Held the clutch in disengaged the whole time I was posting and kept raising and lower the 3 point at the very end probably 4 minutes with clutch disengaged and tractor idling it ran out of oil and started jerking

 

[wore out]

(quoted from post at 20:15:58 07/08/20) Held the clutch in disengaged the whole time I was posting and kept raising and lower the 3 point at the very end probably 4 minutes with clutch disengaged and tractor idling it ran out of oil and started jerking

NOT sure where you are going with this, with clutch depressed , synchro transmission pump isn't operating, so whether it's good or weak, it's immaterial.

And dicking with the loader and 3-point for 4 minutes before running out of oil stored up front in the oil cooler seems normal.

What DOES matter/shorten the time the hydraulics function with the clutch depressed is "high pressure leaks to sump", meaning that a high pressure component is leaking oil that should be going back up front to the oil cooler to keep the main pump fed and instead is leaking off to the "sump".

 

[Tx Jim]

(quoted from post at 00:04:31 07/09/20)

NOT sure where you are going with this, with clutch depressed , synchro transmission pump isn't operating, so whether it's good or weak, it's immaterial.

And dicking with the loader and 3-point for 4 minutes before running out of oil stored up front in the oil cooler seems normal.

I agree with "wore out". I think a "new trans pump" would improve your tractors hyd operation very insignificantly if any at all.

I suggest to cut hay while sun is shining!!

 

[SVcummins]

I’m running out of oil with the clutch engaged . And the loader
won’t raise at all even after a five minute idle if I give it about
ten minutes it will raise one time with the clutch engaged

 

[SVcummins]

Shouldn’t run out of oil with the clutch engaged pedal out
should I ? That’s what I’m asking

 

[SVcummins]

The clutch is not depressed and the loader will barely raise
that’s what I’m asking

 

[Tx Jim]

(quoted from post at 09:29:39 07/09/20) I m running out of oil with the clutch engaged . And the loader
won t raise at all even after a five minute idle if I give it about
ten minutes it will raise one time with the clutch engaged

What type valve controls loader(scv or ind)? If ind has valve been checked to be sure it's setup for closed center OR hasn't blown an internal seal allowing valve to revert to open center which is a CC hyd system pressure/flow thief.

 

[SVcummins]

Jim I’m running it off the couplers off the back of the tractor I
have the stuff that you helped me with earlier and I have the
valve converted for closed center but I have not hooked any
of it up so it still works off the couplers

 

[Tx Jim]

Sorry but "Oldtimers disease'' caused me to forget how your FEL is controlled.

Ok with a 5000 psi gauge install/pressurize each breakaway coupler to see if each side will hold pressure after control lever has been returned to neutral position.

 

[SVcummins]

Don’t feel bad Jim I can’t remember my own stuff let alone
someone else’s . So just plumb a gauge with a John Deere
hydraulic tip on it and plug into the breakaway coupler

 

[SVcummins]

I didn’t have time to get a gauge after work but I did raise the front wheels off the ground with the loader the one scv is holding the other one drifts pretty fast . I guess the next thing to do is get a gauge setup and test the transmission pump per the service manual and see what happens from there . The 3020 will have to put up all the hay by Itself

 

[SVcummins]

Where Is the screen on the main hydraulic pump?

 

[Tx Jim]

Hyd filter in pump is accessed by removing the plugs on RH side of pump head

 

[SVcummins]

The Svcummins hydraslueth 😀